Research On The Design And Preparation Of Flexible Filters

Electronic components fabricated by printed electronics technology have received extensive attention because of its advantages such as flexibility,easy to be prepared in large area,low cost and low pollution.The applications of printed electronics technology mainly include radio frequency identification tag,flexible transistor,flexible sensor,flexible display,solar cells,and so on.The development of the flexible sensor and the miniaturization of the chip create the conditions for the preparation of wearable devices.Thus,people's health can be monitored by collecting physiological parameters.Because the filter can suppress the clutter in the signal,thus the development of wearable device makes the research of the flexible filter become urgently needed.This thesis studied the method of fabricating the flexible RC filter by using ink-jet printing technology with silver ion conductive ink.Then the structure of flexible RC filter was designed and the influence of print parameters in the preparation of the filter was discussed.The flexible RC filter fabricated by this way has good adhesion,and it provides a guarantee for the reliability of the filter.First,this thesis gave the preparation steps of the conductive pattern,and discussed the prepress processing,chemical reactions in the process of the preparation of conductive pattern and the influence of temperature on copper plating effect.The experimental result shows that using polyimide pretreated by NaOH solution as the substrate is beneficial to the even spread of the silver ion conductive ink,and its printing effect is better than that of the untreated polyimide film.The experimental results also show that the conductive pattern can be prepared successfully by printing the silver ion conductive ink on the polyimide pretreated by NaOH solution with the ink-jet printing technology and then making copper deposit on it by electroless copper plating.Then,the structure of flexible RC filter was designed based on the analysis of the working principle of RC filter.And the model diagram of the flexible RC filter was given.Thus,a flexible RC filter was prepared under the suitable printing parameters.The experimental results show that the suitable drop spacing is 25?m in the preparation of the flexible RC filter.And the experimental result also shows that the adhesion of the flexible RC filter prepared by this method can reach 5B grade.At last,the bending test and the filtering characteristic test of the prepared flexible RC filter were carried out.The experimental result shows that the flexible RC filter will not be destroyed in bending test,which indicates that the stability of the flexible RC filter is good.The experimental result shows that the low frequency signal can pass but the high frequency signal is suppressed,which indicates that the flexible RC filter has the filtering characteristics of low pass filter.The flexible RC filter fabricated by ink-jet printing technology with silver ion conductive ink has great adhesion and the filtering characteristics of low pass filter.It is proved that this method is feasible to fabricate the flexible RC filter.And this method has simple processing steps and easy personalized design of the flexible RC filter.In addition,the flexible RC filter fabricated by this method costs much less than that fabricated by the traditional methods.Thus,it provides a new method for flexible filter to fabricate.